Centrifugal gun

ABSTRACT

A centrifugal gun for discharging projectiles at very rapid velocities which gun includes a rotatable impeller having a center of rotation and a peripheral path of movement and having a continuous trackway along which the objects are propelled and which leads from the point of insertion at or near the rotation center to the exit point at the peripheral path. The trackway has an outer concave section and an inner convex section, with the outer peripheral portion of the concave section facing the direction of rotation of the impeller.

United States Patent Inventors Joseph M. Tobin McMurray; Peter 0.Tauson, Badiord Woods; Leonard R. Fleischer, Pittsburgh; Harry F.

Ebner, Clairton, all of Pa. App]. No. 837,441 Filed June 30, 1969Patented Oct. 19, 1971 Assignee Westinghouse Electric CorporationPittsburgh, Pa.

CENTRIFUGAL GUN 5 Claims, 7 Drawing Figs.

US. Cl 124/6, 124/50 Int. Cl F4lb 15/00 Field of Search 124/6, 40, 49,50

I DRIVE MEANS References Cited UNITED STATES PATENTS 1,152,447 9/1915Sproull 124/s0x 1,408,137 2/1922 Parsons... 124/6 1,420,660 6/1922Lombard. 124/6 1,472,080 10/1923 McNaier l24/6 FOREIGN PATENTS 67,0913/1940 Czechoslovakia 124/50 Primary Examiner-Richard C. PinkhamAssistant ExaminerWilliam R. Browne Att0rneysF. Shapoe and Lee P. JohnsABSTRACT: A centrifugal gun for discharging projectiles at very rapidvelocities which gun includes a rotatable impeller having a center ofrotation and a peripheral path of movement and having a continuoustrackway along which the objects are propelled and which leads from thepoint of insertion at or near the rotation center to the exit point atthe peripheral path. The trackway has an outer concave section and aninner convex section, with the outer peripheral portion of the concavesection facing the direction of rotation of the impeller.

PATENTEDUBT 19 197i SHEET 10F 4 2 l 7 mm 4 I 1 1 L E oo 5 u 4 77 6 7 4 70 7 7 FIG.

DRIVE MEANS INVENTORS JOSEPH M. TOBIN, PETER O. TAUSON, LEONARD R.FLEISCHER, AND H WITNESSES AZ,&Z&M 9 (1 AR F. E NER' ATTORNEYPATENTEDUCT 19 ml 3,613.655

sum 3 OF 4 CENTRIFUGAL GUN BACKGROUND OF THE INVENTION 1. Field of theInvention This invention pertains to a rapid-fire mechanical gun. Moreparticularly, it pertains to a centrifugal gun capable of continuouslyfiring at a rate of thousands of rounds of ammunition per minute withoutoverheating.

2. Description of the Prior Art A gradual evolution in small-caliberweapon requirements has occurred during the Korean and Vietnam Wars. Thechange in emphasis has been from accurate slow-fire weapons torapid-fire automatic weapons. Often the enemy is never seen, but isattacked with saturation fire in the direction of his proximateposition. The object of saturation firing is to put as manysmall-caliber bullets as possible into a broad target area.

Prior efforts have been made for increasing the rate of fire of smallcaliber guns. Most machine guns are mechanized with gas or electricallydriven machines to automatically and rapidly charge projectiles into thebreech and to eject empty cartridge cases. The energy for firing theprojectiles comes from the small explosive charge attached to eachprojectile in a cartridge case. Mechanizing the cartridge transportdevices has increased firing rates very significantly. However, thefiring burst has been limited by the large amount of heat released bythe exploding charges, causing overheating of gun barrels. Efforts tominimize or improve the effect of temperature on gun barrels haveincluded water cooling, the development of alloys havinghigh-temperature strength as well as the socalled Gatling gun. However,such efforts have not been completely satisfactory, particularly wheresustained rapid firing is necessary.

Guns that use centrifugal force instead of an explosive charge forshooting a projectile have been known in the prior art. One type ofcentrifugally operated gun involves straight radially extending barrels,such as shown in U.S. Pat. Nos. 1,472,080 and 3,177,862. A limitation ofsuch constructions is that the power required to rotate the radialbarrel is too great to develop an economically feasible rapid-firedevice. Moreover, in US. Pat. No. 3,177,862 radial gun barrels areincorporated with the helicopter blades which slows down the speed ofrotation of the blades due to the absorption of energy by the projectilebullets, or missile as they pass through the barrels.

Another type of centrifugal gun includes a gun barrel having an arcuaterather than radial construction. Such constructions however have limitedthe speed of the projectile for various reasons including (1) rotationof the barrel in a direction reverse to travel direction of theprojectile and (2) the provision of a peripheral barrier which preventsemission of the projectile at the precise moment that it achieves itsmaximum speed at the exit end of the barrel. Such devices are shown inU.S. Pat. Nos. 1,240,815; 1,284,999; 1,408,137; and 1,662,629.

Associated with the foregoing has been the problem of overcoming astrong gyroscopic reaction force of a rotating impeller that resiststurning and moving of a gun when aiming in a plane that is notperpendicular to the axis of rotation of the impeller. One solution tothe problem has been the use of gears and levers of suft'rcientmechanical advantage to overcome the gyroscopic force and therebyfacilitate aiming a gun in the directions that are out of the plane ofimpeller rotation. However, the problem can be better solved byproviding a second impeller which is rotated, say clockwise, to offsetthe gyroscopic force of the first (counterclockwise) impeller. Such asolution has the added advantage of increasing the maneuverability ofthe gun.

A related problem with centrifugal guns of prior construction has beenaccuracy of aiming. Guns of prior construction have been provided withperipheral rims having an opening outlet which was directed in thedirection of fire of a projectile. That construction has limited thespeed of travel of a projectile to the peripheral speed of rotation ofthe impeller.

A problem related to aiming of a projectile is that of feeding theprojectile to an impeller with proper synchronization. If a projectileis to be emitted from the impeller at speeds greatly in excess of theperipheral speed of rotation of the impeller, it is necessary that theprojectile be emitted at the precise moment when it arrives at theperiphery of the impeller. For that purpose the feed mechanism for theprojectiles at the center of the impeller must be synchronized to themoment when the projectile arrives at the periphery of the impeller.Centrifugal guns of prior construction have not been provided withadequate feed means and feed control for such synchronization. I

SUMMARY OF THE INVENTION It has been found in accordance with thisinvention that the foregoing problems may be overcome by providing acentrifugal gun having at least one impeller which includes a continuoustrackway along which a projectile is propelled from the center ofrotation to the periphery of the impeller; the configuration of thetrackway including a convex section near the center and a concavesection adjacent the periphery with the outer peripheral portion of theconcave section extending in the direction of rotation of the impeller.

Accordingly, it is a general object of this invention to provide acentrifugal gun which propels projectiles at velocities greatlyexceeding the rotational peripheral velocity of a cen trifugal impeller,

It is another object of this invention to provide a centrifugal gunhaving a contrarotating impeller for the mutual cancellation ofgyroscopic torque forces. 1

It is another object of this invention to provide a centrifugal gunhaving improved accuracy of aiming andreduced dispersion of shot at thetarget by means of synchronization of pro- 3 5 jectile feed means andthe exit position of the projectile at the periphery of the impeller.

It is a further object of this invention to provide a centrifugal gunhaving an impeller which accelerates projectiles to exit velocitiesexceeding the peripheral velocity of the impeller.

Finally, it is an object of this invention to satisfy the foregoingobjects and desiderata in a simple and effective manner.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of theinvention reference is made to the drawings, in which similar numeralsrefer to similar parts throughout the several views of the drawings, andin which:

FIG. 1 is a vertical sectional view of one embodiment of a centrifugalgun;

FIG. 2 is a horizontal sectional view of an impeller, taken on the lineII-II of FIG. 1;

FIG. 3 is a cross-sectional view of the trackway in an impeller, takenon the line III-III of FIG. 2;

FIG. 4 is an enlarged fragmentary vertical sectional view of a feedcontrol for the impeller;

FIG. 5 is an enlarged horizontal sectional view of the feed control,taken on the line IVIV of FIG. 4;

FIG. 6 is a vertical sectional view of another embodiment of a feedcontrol for the impeller; and

FIG. 7 is a plan view of another embodiment of a pair of counterbalancedimpellers in coplanar positions.

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a centrifugalgun I0 is shown substantially schematically in FIG. 1. It includes animpeller 12, impeller drive means 14, projectile feed means 16, and ahousing 18.

The impeller 12 is a rotatable member, such as a disc, wheel, or an arm,which is mounted on a driven shaft 20 which, by means of intermediategears 22, is operatively connected to the drive means 14 that mayconsist of a prime mover such as an electric motor, or a combustionengine.

The impeller 12 is shown more particularly at FIG. 2 as being a wheel ordisc having at least one, and preferably two,

trackways 24 along which an object such as a projectile 26 is propelledfrom the center of rotation to the periphery 28 of the impeller. Thetrackway 24 has a curved configuration. More particularly, when theimpeller 12 is rotated counterclockwise, as indicated by the arrow 30,the trackway 24 includes an outer portion 34 extending from a circle 32(broken line) to the periphery 28, which portion is concave in thedirection of rotation of the impeller. The trackway 24 also includes aninner portion 36, located within the circle 32, which portion has areverse turn with respect to the outer portion 34. The inner portion 36may be either linear or curved between its inner extremity 38 and thecircle 32; or it may be curved convexly with respect to the direction ofrotation of the impeller 12. Where the portion 36 is curved convexly,there is a point of inflection 40 at the circle 32 where the portion 36joins the portion 34. Thus, the inner end portion 36 of the trackway 24has a reverse inclination with regard to the outer portion 34, wherebythe overall effect of the trackway greatly increases the speed of aprojectile 26 as it leaves the trackway at the periphery 28. The effectof such configuration of the trackway 24 is similar to that of a cestacurve.

More particularly, as a spherical projectile 26 enters the trackway atthe inner extremity 38, it has a rotational velocity of substantiallyzero. Due to the reverse direction, or inner portion 36, of the trackwaywhich reverse direction is contra to the direction of rotation of theimpeller 12, the projectile quickly achieves the rotational velocity ofthe impeller when the projectile reaches the zone of the circle 32, orpoint 40 of inflection. Beyond the point 40 of inflection the rollingprojectile 24 is influenced by the outer portion 34 of the trackway toan extent that its exit velocity at the periphery 28 greatly exceeds therotational velocity of the impeller 12. The inner portion 36 of thetrackway has a center of curvature on the side of the trackway oppositethe center of curvature of the outer portion 34.

Although a single trackway 24 is sufficient for operation of thecentrifugal gun 10, it is preferred that a pair of trackways be providedsuch as trackway 24 and a trackway 42.'In that manner a more balancedweight distribution is provided on the impeller 12 during its operation.

As shown in FIG. 2 when the impeller 12 is rotated at operatingperipheral speeds at continuous rapid firing rates, a sphericalprojectile 26 in the trackway 24 actually travels in an absolute path 44of travel having the form of a spiral as shown by the broken line.

As shown in FIG. 3 the trackway 24 has a cross-sectional opening whichis sufficiently greater than the diameter of a spherical projectile 26to guide the projectile throughout the length of the trackway. For thatpurpose the trackway includes a backwall 46 and a bottom wall 48. Inaddition, where the trackway is completely enclosed, it may include afront wall 50 and a top wall 52.

Although the trackway 24 is preferably disposed in a circular impeller12, the latter may be of any other configuration and may includenoncircular, armlike members extending from opposite sides of the centerof rotation of sufficient width to include a single trackway or pair oftrackways. Moreover, inasmuch as the backwall 46 (FIG. 3) has a dominantinfluence upon the projectile 26 (because of the centrifugal forceinvolved as the impeller rotates), the trackway need not include a frontwall 50 or top wall 52. The bottom wall 48 serves the purpose ofsupporting the projectile 26 and holding it against the backwall 46.

One means for feeding spherical projectiles 26 to the trackway 24 isshown in FIGS. 4 and 5. In order that all projectiles exit at the sameangle of rotation for each turn of the impeller 12, each projectile isfed to the trackway at precisely the same angle of rotation as prior andsubsequent projectiles. The preferred curvature for the trackway 24requires that a projectile 26 be fed preferably at 252 before theprojectile leaves the trackway at the peripheral exit 28. That is accomplished by means of an axial feed tube 54 (FIG. 4) which rotates withthe impeller 12.

As shown in FIG. 1, the upper end of the feed tube 54 communicates witha conduit 56 extending from the feed means 16 where the projectiles arestored in a hopper and fed by gravity or by mechanical means inalignment and into the tube 54. A gate tube 58 is concentricallydisposed around the feed tube 54 and is provided with an opening 60having a size at least slightly greater than the diameter of aprojectile 26. Accordingly, as shown in FIG. 4, as the projectiles 26reach the lower end of the feed tube 54, they roll radially outwardlyover a curved surface 62 at the lower end of the tube and through anopening 64 in the gate tube 58 which opening is alignable with theopening 60. The inner end of the trackway 24 comes into alignment withthe aligned openings 60 and 64 upon each rotation of the impeller 12.When the openings 60 and 64 are aligned, one projectile 26 moves bygravity into the trackway 24. Accordingly, a single projectile 26 isfired over the trackway upon each rotation of the impeller.

In order to aim the gun in the desired direction, an aiming arm 66(FIG. 1) is provided at the upper end of the gun 10, whereby the housing18 as well as the tube gate 58 are rotated on the rotational axis of theimpeller 12 to change the position of the opening 60 at the lower end ofthe gate tube. The aiming arm 66 provides for control of aiming on anazimuth with ease and rapid response. In addition, control of the rangemay be obtained by providing gun-mounting means (not shown) such asbearings or gimbals on an axis perpendicular to that of the shaft 20 ina conventional manner. Where gimbal mounting is used, both azimuth muthand range control of aiming is obtained in a manner conventional withmachine guns, whereby the aiming arm is mounted in a fixed position ofthe housing.

Inasmuch as the position of the opening 60 determines the direction inwhich a projectile 26 is ultimately fired, the housing 18 is alsorotated. As shown in FIG. 1 the housing 18 includes a cylindricalportion 68 which is provided with an arcuate opening 70 through whichthe projectiles 26 are fired. The purpose of the cylindrical portion 68is a safety measure and serves no other function; it does not coact withthe impeller 12 and trackway 24 for the purpose of firing theprojectiles 26.

As indicated the gate tube 58 remains stationary except for manualmovement by the operator to position the opening 60 for aiming the gun.One projectile 26 per revolution enters the trackway 24. Where two ormore trackways 24 are provided in the impeller 12, for increasing rateof fire and for balancing operation of rotation of the impeller, aprojectile 26 is fed into each trackway as its inner end moves intoalignment with the opening 60 of the gate tube 58. For example, if twotrackways are provided, two projectiles per revolution are fed into theimpeller. Moreover, the projectile feed means 16 may be adapted to firea projectile less often than one per revolution of the impeller, therebyreducing the power required without sacrificing projectile velocity.Once a projectile 26 enters the trackway it is fired because no meansare provided for preventing its being fired. The angle at which theprojectile is fired is controlled for following a target by turning thegate tube 58 to enable the projectile 26 to enter the impeller slightlyearlier or later in the period of a single rotation.

For a better understanding of the device, reference is made to thefollowing example:

EXAMPLE Although the embodiment described and shown in the drawings issubstantially disclosed schematically, a suggested design for purposesof illustration is intended for firing a spherical projectile of ironshot having a diameter of about 0.5 inch. This is approximatelyequivalent to the commonly used 50-caliber size shot. The sphericalvolume is 0.0655 in. a and its weight is 0.0185 lb. The firing rateselected for illustration is about 6,000 rounds per minute. The gun willrequire Ill lbs. of shot of ammunition for each minute of continuousfire. The gun may be fired for at least l5 minutes without excessiveheating.

The exit velocity selected for the defensive application is about 1,415feet/second. The kinetic energy for each round is 575 foot-pound/second.At 100 rounds/see, the power required to provide the kinetic energyalone is 105 hp. Because the ball or spherical projectile rolls on onesurface of the track of the impeller, it also acquires a spin velocity.This increases its total energy by as much as 30 percent. The maximumspin velocity is 153,000 r.p.m.

The impeller is one of two necessary moving parts outside of themotor-drive subsystem or drive means 14. It provides flywheel action(rotational inertia) to transfer kinetic energy through the ball withless than 0.1 percent variation in the rotation speed. A second rotor isprovided to rotate in the opposite direction to cancel the gyroscopicreaction incurred when the weapon is turned at an angle to the plane ofrotation to follow a target. ACcordingly, as shown in FIG. 1, the shaft61 is operatively connected to an impeller (not shown in the drawing)having a construction substantially equal to that of the impeller 12.Thus, the gun is preferably a double-barreled" weapon.

By proper shaping of the curve of the trackway 24 a spherical projectile26 accelerates to at least 50 percent greater velocity than theperipheral speed of the impeller. The preferred diameter of the impeller12 is about 3.82 feet. An impeller firing 6,000 shots per minute at1,415 ft./sec. requires an engine of about 200 hp. such as a gas turbinewhich weighs approximately 300 lbs.

With the impeller rotating counterclockwise at 100 revolutions/second(6,000 revolutions/min.), a constant accelerating force of 652 pounds isapplied to a spherical projectile having a diameter of 0.5 inch. Theperipheral velocity of the impeller is 1,200 feet per second and thevelocity of the projectile at the exit is 1,800 feet per second with anacceleration of 198,500 ft./sec. The impeller rotates about 252 betweenthe time the projectile enters the trackway and the time it exits whichis 0.01 second later. In FIG. 2 the actual path of the projectile duringits acceleration in the impeller is indicated by the broken line 44. Thespaced positions on the actual path are disposed at equal timeintervals.

During operation of the gun some heat is generated due to frictionbetween the impeller and the projectile. The heat generated in impartingthe desired velocity to the projectile is substantially evaluated fromthe power input which is 74 B.t.u./sec. For an impeller having adiameter of 3.82 feet the impeller area is approximately 23 sq. ft.Assuming all of the heat is removed by air cooling using a 20 F.temperature rise the mass flow of air required for cooling is about 15.4pounds per sec. Stator vanes 74 are provided within the housing 18.Rotor vanes 76 are provided on the upper and lower surfaces of theimpeller. The vanes 74 and 76 operate as centrifugal blowers forproviding the necessary cooling air which will require an additional16.8 hp.

The air is pulled by the vanes from the upper and lower sides of theimpeller 12 as well as from the trackways 24 via a clearance space 75between the periphery of the impeller and the housing. The air is thendirected into a scroll-like portion 77 (similar to hydraulic turbines)of the housing 18, from where it is exhausted.

The impeller drive means 14 includes the bevel gears 22 for the purposeof driving the impeller 12 as set forth above as well as acontrarotating impeller not shown at the lower end of the shaft 21. Inorder to start the high-inertia impeller, a hydrodynamic drive may beused. This type of drive may be used to control speed up to percent ofspeed, maintaining a variation within 1 percent, and couple the power tothe impeller with an efficiency of approximately 90 percent.

The power required for the gun 10 using the indicated parameters for theimpeller in the spherical projectile having a diameter of 0.5 in., canbe summarized for one impeller as follows:

105-hp. Kinetic energy 31-hp. Spin energy 102-bp. Loss (assuming 60percent efficiency) 17-hp. Air-cooling 255-bp. Engine Drive 7 This powermay be delivered at high horsepower to weight ratio and a high r.p.m.using a small gas turbine. The estimated total weight of the weaponsystem for the above unit is under 400 lbs.

The weapon in its simplest form consists of one moving part, theimpeller. The preferred ammunition is a spherical steel ball. Bysuitable modifications to the gun, it is capable of firing atrates up to12,000 rounds per minute with shot velocities up to 3,500 feet persecond for shot having a size up to 35 mm.

Another embodiment of the invention is shown in FIGS. 6 and 7 in whichfeed means generally indicated at 78 replace the feed means 16 of theembodiment of FIG. 1, and in which a pair of impellers 80 and 82 (FIG.7) are disposed in coplanar positions with respect to each other insteadof coaxial positions as described for the embodiment of FIG. 1. As shownin FIGS. 6 and 7 the housing 18 is modified to provide for a pair ofcircular housing portions 84 and 86 surrounding the impellers 80 and 82,and for providing a projectile exit port 88 by which sphericalprojectiles 26 are shot from the gun. Thus, two streams of projectiles26 are emitted when the gun is fired through the exit port 88.

The feed means 78 which is identical for both impellers 80 and 82, isdescribed herein for the impeller 80 as shown in FIG. 6. The meansincludes a hopper 90 where spherical projectiles 26 are stored over arotatable thrower 92 which is a disc mounted on a driven axis connectedto the drive means 14 by connecting drive shafts and bevel gearsincluding a bevel gear 94. The thrower 92 is synchronized to rotate oneturn for each turn of the impeller 80. A notch 96 is provided at theperiphery of the thrower 92 so that as the notch passes through thelower portion of the hopper 90 a projectile 26 enters the notch and isbrought to the lower position from where it is thrown to the right asviewed in FIG. 6, and into the trackway 24 of the impeller 80. Thetrackway in all other respects is constructed in a manner similar tothat shown in FIG. 2.

The hopper 90 includes a lower arcuate portion 98 on one side of thethrower 92 and an arcuate portion 100 on the other side of the thrower92. The lower end 102 of the hopper portion 98 is disposed above asurface 104 of the impeller 80 by a distance sufficient to permitclearance of a projectile 26 as it passes from the thrower 92 into thetrackway 24. The arrival of the projectile 26 as controlled by thethrower 92 is synchronized with the position of the inner end of thetrackway 24 to enable the projectile to enter the trackway. If for anyreason there is a misfire so that the projectile does not enter thetrackway, the projectile which misfires passes upwardly through aclearance space 106 between a curved surface 108 of the impeller and thehopper portion 98. Thus the misfired projectile 26 moves out ofinterference with subsequently delivered projectiles.

Operation of the feed means 78 is controlled by a manually operatedlever 110 which is moved between the solid line position and a brokenline position 112 as shown in FIG. 6. An arcuate member 114 which in thefiring position is disposed between the hopper portion 100 and thethrower 92 so that projectiles 26 are free to drop into the notch 96 asthe filler rotates in the counterclockwise direction as indicated by thearrow 116. When however the lever 110 is in the alternate position 112the arcuate member 114 is disposed over the lower portion of the hopper90 to prevent projectiles 26 from entering the notch 96.

In operation the embodiment of the gun shown in FIGS. 6 and 7 isoperated by filling the hoppers 90 with spherical projectiles 26. Thethrowers 92 and the impellers 80 and 82 are then actuated and brought tooperating speed. Firing is initiated by moving the lever 110 from theclosed position 112 so that a projectile 26 is free to engage thenotches 96 in the thrower 92. A properly synchronized projectile 26enters the trackway 24 of each impeller 80 and 82 and is acceleratedthereby in the manner described with regard to the first embodiment, toan absolute speed that is approximately 50 percent greater than theperipheral velocity of the impeller under constant acceleration theprojectile is released at a constant angle of rotation of the impellers80 and 82 and passed through the exit port 88 at the outer extremity ofthe trackways. The direction of firing is constant when the projectilesare inserted in the trackway with precise synchronization with thethrowers 92.

Accordingly the device of the present invention provides for acentrifugally operated rapidly firing mechanical gun which may usespherical or a nonspherical projectile as well as explosive ornonexplosive bullets. Moreover, although the apparatus is described asproviding a centrifugally operated gun, the apparatus may also be usedfor sandblasting or metal peening with appropriate modifications.

It is understood that the above specification and drawings are merelyexemplary and not in limitation of the invention.

What is claimed is:

1. Apparatus for firing a projectile by track-controlled radial andtangential accelerations utilizing centrifugal force, comprising arotatable impeller having a center of rotation and a periphery, meansfor rotating the impeller, the impeller having a continuous trackwayalong which the projectile is propelled and which leads from the centerof rotation to the periphery, the trackway having an outer concavesection and an inner convex section adjacent to the center of rotation,the concave section facing the direction of rotation of the impeller andhaving a peripheral extremity extending into the direction of rotationof the impeller, there being a point of inflection between the convexand concave sections which point is nearer the center of rotation thanthe periphery, and means for feeding projectiles to the trackway at thecenter of rotation, whereby projectiles are emitted from the peripheryof the trackway at velocities exceeding the peripheral velocity ofrotation of the impeller.

2. The apparatus of claim 1 wherein the projectile-feeding means areintermittently operative for releasing projectiles into the trackway andincludes means for controlling release of projectiles.

3. The apparatus of claim 1 wherein the outer end portion of thetrackway is substantially a spiral.

4. The apparatus of claim 1 wherein the inner end portion of thetrackway extends substantially radially.

5. The apparatus of claim 1 wherein the center of curvature of theconcave section is on one side of the trackway and the center ofcurvature of the convex section is on the other side of the trackway.

1. Apparatus for firing a projectile by track-controlled radial and tangential accelerations utilizing centrifugal force, comprising a rotatable impeller having a center of rotation and a periphery, means for rotating the impeller, the impeller having a continuous trackway along which the projectile is propelled and which leads from the center of rotation to the periphery, the trackway having an outer concave section and an inner convex section adjacent to the center of rotation, the concave section facing the direction of rotation of the impeller and having a peripheral extremity extending into the direction of rotation of the impeller, there being a point of inflection between the convex And concave sections which point is nearer the center of rotation than the periphery, and means for feeding projectiles to the trackway at the center of rotation, whereby projectiles are emitted from the periphery of the trackway at velocities exceeding the peripheral velocity of rotation of the impeller.
 2. The apparatus of claim 1 wherein the projectile-feeding means are intermittently operative for releasing projectiles into the trackway and includes means for controlling release of projectiles.
 3. The apparatus of claim 1 wherein the outer end portion of the trackway is substantially a spiral.
 4. The apparatus of claim 1 wherein the inner end portion of the trackway extends substantially radially.
 5. The apparatus of claim 1 wherein the center of curvature of the concave section is on one side of the trackway and the center of curvature of the convex section is on the other side of the trackway. 